7x57 problem

[JonnyC]

Hi All,

Just started loading for 7x57 with a lee collet die set..trouble is, my 7mm bullets (.284") drop right through the neck even when neck sized as tight as possible!

Spoke to the importer and they said for the 7x57 you need .285" bullets...but when I asked how that makes it possible for most people to shoot Nosler 7mm bullets in 7x57, they said it was just un-explainable!

So, question is,,,do I bin all my 7mm bullets and look for some magical .285" bullets??? or is there another re-sizing die set which can tighten the neck sufficiently to use 7mm bullets?

Never had this problem with any other calibres I've been reloading for, so am a little boombazed...

 

[JRS]

What kind of brass are you using? The .285 is a European size bullet, and is bigger in diameter by roughly one quarter the thickness of a human hair. Shelve the Lee dies and pick up Redding, Forster or RCBS.

 

[Barlow]

Sounds to me like the mandrel is too big. Mic it and see what it measures. I would think it should be in the .282 area to work right. Barlow

 

[Ringostar]

I agree with Barlow. Measure your mandrel. I have a collet die in 7 x 57, the mandrel is .282. It works fine to size necks on my 284 cases.

 

[JonnyC]

thanks guys. returned the lee dies so can't measure them.

using once fired norma brass, rws and federal, all display the same problem despite two being european and one american.

I assume it must be a matter of the dies simply not be flexible enough in their adjustment scale then..otherwise no one would be able to shoot american bullets in norma, rws, lapua, etc. brass, which makes zero sense to me.

keep replies coming

 

[Barlow]

I have loaded 7x57 ammo for many years, and it's not complicated. If a .284 diameter bullet is not gripped after sizing, a .285 diam won't have enough neck tension either. LCD dies work fine, and I'm sure the mandrel was too big. Let us know what you hear from Lee. Good luck, Barlow

 

[Laurie]

using once fired norma brass, rws and federal, all display the same problem despite two being european and one american.

They were fired in the same rifle? Or if not, you had full-length sized them before using the LCD? If previously fired with heavy loads / high pressures in a slack chamber, the upper case-body will often expand too much to enter the collet section properly and the die won't work.

 

[rogn]

Sure sounds like the mandrel in the LCD is too large. Due to its being too large there's no way to get tnsision to hold the bullets. Now if the same problem exists with the other FL dies or---? Begs the question have you measured the "7mm " bullets that you have. Could they have beed mislabeled? Ive loaded 7X57 since back in the early 60s and its one of the easier cartridges to load. Wonder if you got some mislabeled 0.277 bullets.

 

[Uncle Ed]

If you are dead set on neck sizing then just buy a standard neck sizing die if you have a milsurp rifle.

If its not a milsurp rifle with a long fat chamber then use a standard full length die.

I highly recommend Forster full length dies with their high mounted floating expanders.

Forster Bench Rest Full Length Sizer Die
https://ads.midwayusa.com/product/154905/forster-bench-rest-full-length-sizer-die

 

[Barlow]

O.P., What did you ever hear from Lee? Barlow

 

[bsekf]

Interested in what Lee says too. You could have custom made the mandrel with your drill press and emory cloth.

 

[Dusty Stevens]

Youd be way ahead to ignore the lee stuff and get a good fl die from rcbs or redding especially using once fired brass and more especially in a milsurp rifle

 

[liseo]

You must press up the collet very hard , so the jaws press the neck against the mandrel.

If you've already done this, discard my suggestion.

 

[Jacob.A]

Never had an issue with standard US 7mm bullets with mine, I use Hornady dies.

 

[Ggmac]

Fill out your profile so we know your location . The U.K. ?
Get a set of full length dies .
Did you turn the brass necks ? European , some , have thinner neck walls .
Was it new or used brass ?
What rifle are you going to use it in ?
How long have you been reloading ?
Is this for competition ?
Hunting ?
It's easy to modify a Lee collet die mandrel but it requires knowledge of its limits and design function

 

[normmatzen]

I have been loading 7X57 for a few years with a Lee Collette die with excellent results.

Did they send you a 8X57 die or Mandrell by mistake. That is about 0.032" too big? Actually,
I don't think you could stuff a 8mm mandrel in a fired 7X57 case, but maybe a 0.308 mandrel would go?